An unexploded ordnance (UXO) survey instrument that simultaneously collects total field magnetic data and frequency domain electromagnetic (FDEM) data was developed and tested for the detection and characterization of buried UXO objects. The system comprised an FDEM sensor operating at a single frequency of 9.8 kHz and a cesium vapor magnetometer. The system was tested in dynamic survey (detection) and cued analysis (characterization) modes at the Naval Research Laboratory Blossom Point UXO test facility in Maryland and the U.S. Army Engineer Research and Development Center (ERDC) UXO test site in Mississippi. During these tests, electromagnetic (EM)-induced bias in the magnetic data was mitigated by physically offsetting the magnetometer from the EM transmitter coils. In both detection surveys, the aggregate detection rate exceeded the detection rates for the individual component sensor technologies. The cued analysis tests performed at Blossom Point showed that features can be estimated using physics-based analyses. The location estimate errors provided by these analyses were consistently less than 0.3 m. The cued analysis data collected at the ERDC UXO test site have been used to provide position estimates for most of the emplaced targets at this site.